The invention relates to a mixing apparatus for fluids and, more particularly, to a mixing apparatus for mixing, blending or diluting two or more liquids such as a viscous polymer liquid and water into a substantially homogenous mixture.
It is often desirable to form a substantially homogenous solution of two or more difficult to mix liquids, such as water and oil or polyelectrolytes. Polyelectrolytes are polymers that have a high molecular weight, typically within the range of 1 to 10 million. Polyelectrolytes are often used as flocculating and clarifying agents for the clarification of water and in sewage treatment.
Diluted polyelectrolytes are utilized in industrial water treatment processes. However, such polyelectrolytes are typically shipped to water treatment facilities in concentrated liquid form and then pumped into stirred tanks containing water. The concentrated polyelectrolytes are mixed and diluted with the water by mechanically-operated impellers to make an homogenous solution. Mechanical agitation of such solutions, however, undesirably creates a great deal of shear that detrimentally affects the polyelectrolytes.
U.S. Pat. No. 4,522,502 discloses a mixing apparatus in which an impeller mechanism is mounted within a mixing chamber. The apparatus is designed to mix the polyelectrolytes and water with high torque and low shear so as to cause less damage to the polymer chains comprising the polyelectrolytes.
Nonetheless, utilization of less-intensive mechanically induced mixing, with paddle wheels or short detention time, will result in at least some undesirable side effects including mechanical shearing and, as well, subjects the process to interruptions due to breakdown of the moving parts. The less intensive mixing, moreover, can result in a mixture which is not homogenous.